# my first project

#### martin the warrior

Aug 10, 2015
35
Ok for my first ever electronics project I want to build a brake light and turn signal circuit for my bicycle. this is the circuit I built up. I need a better or rather cheaper version of the electronic flasher they are $8 each. Im also going to but the switches on the ground side so they last longer. also ill need a way to space and nold my LEDs. I will also need a soldering iron will a$10 one be all right for projects like this? also if there is anything im missing or any ideas you guys have im all ears. thanks!!

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#### martin the warrior

Aug 10, 2015
35
ok i dont know how to edit the post the option is gone. but I looked up other ways to create a pulse and found the 555 timer the set up is simple enough. the formula I found to calculate the HZ of the timer is Frequency = 1.44 / {(R1 + 2R2) * C1} but the timer set up i found only uses one resistor between pins 8 and 7 and he said to change the resistance and said nothing about the capacitor, in order to change HZ. like I said the way he set up is simple (and worked) but I want a 1HZ timer so I looked up a formula and got that. plus I use a 9v the voltage going into the timer will be different if say I use a 12v and the formula doesnt ask for starting voltage.

#### Gryd3

Jun 25, 2014
4,098
ok i dont know how to edit the post the option is gone. but I looked up other ways to create a pulse and found the 555 timer the set up is simple enough. the formula I found to calculate the HZ of the timer is Frequency = 1.44 / {(R1 + 2R2) * C1} but the timer set up i found only uses one resistor between pins 8 and 7 and he said to change the resistance and said nothing about the capacitor, in order to change HZ. like I said the way he set up is simple (and worked) but I want a 1HZ timer so I looked up a formula and got that. plus I use a 9v the voltage going into the timer will be different if say I use a 12v and the formula doesnt ask for starting voltage.
The 555 timer uses something called a voltage divider which it uses as a reference as it charges and discharges the capacitor to turn on / off. In theory, if you double the voltage, the capacitor charges quicker, BUT the reference is also higher so there is no need to fret too much about a very specific voltage.
FYI, there are LOTS of 555 timer samples online, and if you are creative with your switches, you can control BOTH turn lamps with one 555 timer. (A second timer can be used to flash the brake light... a lot of cyclists have this behaviour, as it catches more attention.)

#### martin the warrior

Aug 10, 2015
35
here is my new and hopefully improved circuit. Im putting the turn signal switches on the ground side they will ground both the LEDs and 555 timer. I think if I ground the 555 timer there by the pink dot the timer should not operate unless either switch grounds it. everything grounds at the 9v ground symbol just to clarify that, microsoft paint is not the great (lol)

#### Gryd3

Jun 25, 2014
4,098
here is my new and hopefully improved circuit. Im putting the turn signal switches on the ground side they will ground both the LEDs and 555 timer. I think if I ground the 555 timer there by the pink dot the timer should not operate unless either switch grounds it. everything grounds at the 9v ground symbol just to clarify that, microsoft paint is not the great (lol)
View attachment 21429
At first glance. It looks good to me.
Something you can use would be digikey's "SchemIt"

#### martin the warrior

Aug 10, 2015
35
ok here is the final revision. I added diodes in parallel to the 555 timer ground circuit so when I hit a switch it only grounds the selected one. there are going to be 15 LEDs for left turn 15 for right turn and 15 for brakes. the LEDs in each group will be parallel to each other then they will all fed into the same resistor before going to ground.

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